Grinding machine



July 4 1939- c. HERFURTH 2,164,875

GRINDING MACHINE Filed Jan. 31,v 1958 6 Sheets-Sheet l Hmmm.

\ 1NVENTOR. BY /@Qff #www ATTORNEY.

July 4, 1939.

C. HERFURTH GRINDING MACHINE Filed Jan. 51, 195B 6 Sheets-Sheet 2 mmnmmn...

ATTORNEY.

July 4, 19399 Filed Jan. 31, 1938 6 Sheets-Sheet 5 INVENTOR. @4F25 /Zw/z//PM WMM/m..

ATTORNEY.

jugy 4, i939. Q HERFURTH 2,164,875- l @BINDING MAGHINE Filed Jan. 31, 1938 6 sheets-sheet 5 'l Jy x45 l'l' 4a -24 24d fo li S z/ 2.2/ 220.24? 0 Mgg lf@ 70 I N VENT OR. (2H/aff dce/0PM 5] gf 5/ azul/07ML,

' ATTORNEY.

July 4, 1939e HERFURTH 2,164,875

GRINDENG MACHINE Filed Jan. 3l, 1938 6 Sheets-Sheet 6 www ATTORNEY.

llatented July 4, 1939 UNITED STATESl 2,164.87 GRINDING MACHINE Charles Herfurth,

Cincinnati, Ohio, Cincinnati Grinders Incorporated,

assigner to C Cincinnati,

Ohio, a corporation of Ohio Application January 31, 1938, Serial No. 187,815

16 Claims.

'I'his invention relates to grinding machines andA more particularly to improvements in the transmission and control mechanism thereof.

One of the objects of this invention is to con- 5 trive a mechanism which will facilitate control of the -feeding movement between the grinding wheel and the work under varied conditions, and which is sulciently versatile to yield manual, power, or automatic cyclic control.

Another object of a mechanism ofthe character described which will provide for different methods of operation without unnecessary duplication of parts.

A further object of this invention is to improve the efficiency of an automatic cyclic control mechanism whereby at any point in the cycle, the movement may be speeded up manually, and at will, without interfering with the established cycle. A still further object of this invention is to provide a novel control mechanism for an hydraulic motor actuator which will yield an uncontrolledv fast rate and a monitored feed rate in automatic succession.

other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings illustrative of one embodiment thereof, but it 30 will be understood that any modifications may be made in'the specific structural details within' the scope of the appended claims without departing from or exceeding the spirit of the invention. Referring to the drawings in which like ref- 35 erence numerals indicate like or similar parts:

Figure 1 is a front elevation of a machine tool embdying the principles ofV this invention.

Figure 2 is a vertical section through the machine taken on the line 2-2 of Figure 1.

Figure 3 is a section on the line 3-3 of Figure 1 showing the manual and power control mechanism.

Figure 4 is a detail section on the line I-I of Figure 3. 45 Figure 5 is a diagrammatic view of the portion of the hydraulic control circuit which governs manual and power operation.

Figure 6 is a section on the line 6-8 of Figure 1 showing the details of the servo-control mech- 50 anism.

Figure 7 is a detail section showing the control mechanism for one of the rate control valves.

Figure '7A is an expanded view of the cam path in the adjusting member shown in Figure '7.

this invention is to provide Figure 8 is a diagrammatic view of the hydraulic control circuit for effecting automatic cyclic movements.

Figure 9 is a detail view of the servo-valve parts when in tion.

This invention deals primarily with a mechanism for controlling the approaching and retractive movements between a grinding wheel and a work piece, such movements often being referred to as infeeding to distinguish from traversing l0 movements. A complete infeed cycle is one beginning with the wheel at rest in'a retracted position, and finishing in that same position. Normally one infeed cycle is executed for each ground surface to be produced on the work.

One of the objects of this invention is to provide versatility in the manner of executing an infeed cycle, whereby during grinding of a single special work piece, the infeed may be manually controlled; or during the grinding of dupli- 20 cate surfaces on a large number of work pieces, it may be semi-automatically or completely automatically controlled. In other words, this invention aims to have available the most emcient cycle for producing the work in hand, and with- 2g; out the necessity of making time consuming changes of set-up.

In Figures 1 and 2 of the drawings. there is shown a wheel head I0 and a work table Il, supported on a bed I2. As illustrated, the wheel head slides on guideways i3 carried by the bed for movement toward and from the work table I l, and this movement is commonly known in the art as the infeed movemen It will, of course, be obvious that the wheel head could be made stationary, and the work table Il moved toward and from the grinding wheel to execute the infeed movement as has been done in the past, and it isl to be understood that the mechanism of this ini vention is equally applicable to whichever slide is designated as the moving slide.

In the drawings, the movement of the wheel head slide i0 is effected in one direction by a screw and nut, the nut Il being secured for movement with the slide I0, and the screw i5 be- 45 ing rotatably journaled in the bed l2, whereby when the screw is held againstaxial movement and rotated, the slide lll will bem'oved in a direction corresponding to the direction of rotation of the screw. I

Rotation of the screw I5 may be effected' manually by means of the following mechanism. As shown in Figure 2, a gear'wheel I6 is rotatably journaled in the bed and has a splined connection at il with the cross feed screw I5. This showing the relation starting posigear is operatively connected through reduction gearing |8 to a pinion I9 secured to the end of shaft 20. This shaft is connected by a universal jointed shaft 2| to a coupler 22 which has a splined hole for receiving the splined end 23 of shaft 24.V The shaft 24 is antifrictionally supported by needle bearings 25, Figure 3, in the bore of a gear 26 having an elongated hub 21, which, in turn is antifrictionally supported by needle bearings 28 in a plate 29 attached to the front of the machine. The shaft 24 has an enlarged spline portion 30 upon which is slidably splined a clutch member 3|. When the clutch is shifted into the position shown in Figure 3 by means of the shifter fork 32, it engages clutch teeth 33 formed on the face of the gear 26, whereby the shaft 24 is operatively coupled through the gear train 34, shown in Figure 2, to a manually operable hand wheel 35. It will now be evident that by properly positioning the clutch 3|, the wheel slide `I0 may be manually adjusted by the hand wheel.

Due to the reduction ratio in the gearing be tween the hand wheel and the screw, only a small movement of the wheel slide can be effected in one rotation of the hand wheel. Therefore, when large movements of the wheel slide are to be effected, a power operable mechanism is made available for rotating the shaft 24. This mechanism is controlled by a hand lever 36 which is mounted on the front of the machine within easy reach of the operator. This lever has two planes of movement. In other words, the lever is supported for universal movement by a ball shaped portion 31 secured in a socket 38 formed in a rotatable sleeve 39, and the operating end of the lever is provided with a ball shaped portion 40 which interfits in a socket 4| of control rod 42. The sleeve 39 is keyed for rotation with a valve sleeve 43, and is held against axial movement by a cap 44 threaded in the end of the valve sleeve. It will now be evident that rotation of lever 36 in a plane at right angles to the plane of Figure 3 of the drawings, will effect rotation of sleeve 39 and valve sleeve 43. This rotation will be in a clockwise direction, as viewed in Figure 1 of the drawings, and should have sufficient extent that a pin 45 fixed with the sleeve and projecting into a circumferential slot 46 to prevent axial movement of the control rod 42, will enter the elongated slot 41 thereby releasing the control rod 42.

'Ihe valve sleeve 43 has a gear segment 48 fixed on the other end which intermeshes with pinion teeth 49 on a rotatable shaft 58. 'I'he pinion teeth 49, as shown in Figure 4, intermesh with a rack bar 5|, which is held against rotation by a fixed pin 52 riding in a slot 53 formed in the side of the bar. The rack bar has a reduced portion 54 which passes through the center of a spring 55 interposed between the end of the rack bar and the closed end 56 of the bore 51. It Will now be evident that rotation of the hand lever 36 in a clockwise direction will effect rotation of the valve sleeve 43 thereby moving the pin 45 into the elongated slot 41, and concurrently rotating the shaft 50, compressing spring 55.

The shaft 50 has a cam groove 58 formed in the periphery thereof containing a follower 59 which is rotatably mounted on the end of a xed pin 60. Therefore, upon rotation of the shaft 50, the cam groove 58 co-actingwith the xed follower will cause axial movement of shaft 50 to effect shifting of clutch 3| connected thereto. This connection is effected .by reducing the end 6| of the shaft 50, and providing a spool 62 thereon for receiving a pin 63 formed in the end of the clutch shifter lever 32 which is pivotally supported in its middle at the point 613. The spool 62 is relatively movable with respect to the reduced portion 6|, and springs 65 are interposed betweeen each side of the spool and the opposite ends of the reduced portion so as to provide a certain amount of resiliency in the connection between the shaft and the lever, so that if for any reason the clutch teeth on the member 3| do not engage immediately, there will be no breakage of the parts, whereby the control meechanism may complete its movement leaving subsequent engagement of the clutch teeth to be effected upon rotation of either of the driving members.

When the clutch 3| is shifted by the shaft 56, the clutch teeth thereon engage clutch teeth 66 formed on'the end of the drive shaft 61 of a rotary hydraulic motor 68. Actuation of this motor in either direction is also controlled by the manual control lever 36.

It will be obvious from Figure 3, that after the hand lever has been rotated to position the pin 45 carried by the valve sleeve in the elongated slot 41, that the valve plunger may be moved relative to the valve sleeve upon movement of the lever 36y in a clockwise or counterclockwise direction, as viewed in Figure 3.

As diagrammatically illustrated in Figure 5, the valve sleeve has a port 69 which is supplied with pressure through channel 10 by a pump 1|; two exhaust ports 12 and 13 which are connected by channel 14 to reservoir 15; and a pair of motor ports 16 and 11 which are connected by channels 18 and 19 respectively to the hydraulic motor 68. The valve plunger is provided with a central spool which normally is in a position to close port 69 but it will be obvious that upon movement of the spool in either direction, that the pressure port 69 will be connected to one of the motor ports, and the other motor port will be connected to reservoir, resulting in rotation of the motor. Means have been provided for normally holding the spool 80 in the position shown, and consists of a detent bell crank 8| having a ball shaped end 82 fitting in a socket 83 formed in the valve plunger and a V-shaped end 84 engageable by the spring pressed detent 85.

Therefore, to effect power rotation of the screw I5, the operator moves the lever 36 in a clockwise direction, as viewed in Figure 1, to effect engagement of the clutch 3| with the hydraulic motor 68, and then moves the lever in a second plane either towards him or away from him to effect rotation of the hydraulic motor to cause movement of the wheel toward the operator or away from the operator; and holds the lever in either one of these two positions until the desired movement has been completed. The lever 36 is then released whereupon the spring pressed detent 85 will center the lever in one plane, and the spring 55 will rotate the lever in a counterclockwise direction to disconnect the clutch 3| from the motor, and connect it to the manually operable gear 26 whereby the parts will be again conditioned for manual operation.

In addition to the above mechanism for effecting movement of the grinding wheel at will, by either manual or power actuable means, there has also been provided a hydraulic mechanism for effecting a complete automatic cycle of movement of the grinding wheel when the machine is utilized for production work. In this case, the grinding wheel can be manually positioned by rotation of the screw l5 in accordance with the g5 landere size of the work to be ground, after which the subsequent movements are effected by axially moving the screw. To this end the screw I5 is supported for axial movement having a sliding spline connection with the gear I8 as previously explained, while the other end is slidably mounted in a iixed bearing 89. The rear end of the screw is provided with a piston 81 which has an antifriction connection 88 with the screw whereby the screw may` rotate relative to the piston.

The piston is contained in a cylinder 89 which is connected by a hydraulic channel 90, as shown in Figure 8, to a port 9| of a servo valve indicated generally by the reference numeral 92. It will now be evident that if fluid pressure is admitted to cylinder 39, that the piston and screw will be advanced thereby advancing the grinding wheel, and this movement will continue until a stop 93 carried by the screw engages a positive stop 94. This will limit the movement in one direction while the movement in the other direction will be limited by the length of the cylinder 89. The maximum amount of movement is made sumcient to allow the usual amount of retraction of the grinding wheel for work removal and insertion purposes, as well as the required amount for grinding.

It will be obvious thatthe piston and cylinder combination 81-89 will only effect power movement in one direction. Movement in the other direction is effected by admitting fluid pressure to the closed end of cylinder 95 which is .mounted on the wheel head |0. This cylinder has a contained piston 98 which is connected by a piston rod 91 to a fixed part 90 of the bed whereby the piston remains stationary and the cylinder moves. Pressure uid is conveyed to the cylinder through the piston rod 91 and transverse holes 99 yformed in the end of the piston rod adjacent the face of the piston. Fluid for this cylinder is supplied from a separate pump |00 through channel |0I.

4The pump |00 has a relief valve |02, which is set to produce a higher unit .pressure than the pressure supplied to cylinder 89, wherebyv they vcylinder 95 may be made smaller in diameter,

but the total resultant'force in cylinder 95 urging return movement of the wheel slide is only one half of the total force exerted in cylinder 99 to cause forward movement of the wheel slide. It therefore follows that when fluid pressure is admitted to cylinder 89, the wheelslide will Abe advanced against the opposition of the' pressure.

in cylinder 95 and that when the cylinder 89 is connected to reservoir, the wheel slide will be returned by the pressure in cylinder 95'. It will be noted that the cylinder 95 is continuously connected to the pump |00 'and this serves an additional purpose in that the feed nut |4 is continuously urged in one direction against the screw I5 thereby eliminating 'any back lash between the two,parts. It should also be noted that this continuously acting pressure holds the screw against advance movement during manual or power rotation of the screw. A

The servo-valve 92 consists of an outer rotatv able and axially movable sleeve |03, whichhas a on the end of a fixed spiral cam` groove |04 formed in its periphery, into which iits a follower |05 rotatably mounted shaft |05. A second sleeve |01 is slidably mounted within the outer sleeve. When the parts are in a starting position, as shown in Figure 9, a spring |08 continuously urges the sleeves in opposite directions, and the movement ofv'sleeve |01 is limited by the casting while the movement of sleeve |03 is limited by the follower |05. A mounted in the bore of the inner sleeve, and a spring ||0 is interposed between a shoulder on the inner sleeve and a shoulder I|2 on the end of the valve plunger, for continuously urging the valve plunger in the same direction relative to the inner sleeve that the inner sleeve is urged by the spring |08.

The spring |08 is stronger than the spring ||0 and therefore holds the flange ||3 of the inner sleeve against the shoulder ||4 on housing ||5, and the outer sleeve against the follower, thereby taking out any backlash between the follower and the cam surface. In turn, the spring ||0 urges the plunger |09 in the same direction until the head ||6 on the end of4 the plunger abuts a shoulder ||1 formed on the casing I|5. This resultsV in the annular groove ||8 formed in the valve plunger |09 interconnecting a pair of ports ||9, |20; and these ports are continuously connected with channels |2| and |22 respectively, regardless of relative movement Vbetween the inner and outer sleeve.

The channel |2| is connected to the chamber |23 in the right hand end of the automatic start and stop valve |24, and the channel |22 leads to the reservoir |25, whereby no pressure will be present in the chamber |23 and the plunger |26 of the start and stop valve will be in an extreme right hand position as viewed in Figure 8.

Pressure is supplied to the servo-valve from a pump |21, which has an intake- |28, through which fluid is withdrawn from a reservoir |25; and a delivery channel |29, which has a first branch |30, connected to annular groove 13| formed in the outer sleeve |03 of the servo-valve; and a second branch |32 terminating in ports |33 and |34 of the pilot valve |35, and port |36 of the reversing valve |31. The annular groove |3| is in continuous communication with a port |38 formed in the inner sleeve, whereby, when the plunger |09 is shifted relative tothe inner sleeve |01, the port |38 will be connected to the port ||9 to cause shifting of the start and stop valve plunger |25 to the left. The fluid pressure in the annular groove |3| continues to channel |39, which has a rst branch terminating in pressure port |40 in the outer valve sleeve, and a second branch terminating in port |4| of the automatic start and stop valve. The outer sleeve ofthe servo-valve is also provided with an exhaust port |42 which` communicates with the return line |22.

The inner sleeve is provided with two annular grooves |43 and |44 which |45 of suillcientwidth to close the port 9| which leads to thefeed cylinder 09. The port 9| is A closed when the servo-valve is in a starting `posimovement is for eifecting axial reciprocation of a manually operated start and stop valve plunger |5| which has a slot |52 into which ts the ball shaped end |53 of lever |49.

valve plunger |09 is slidably are separated by spool By rotating lever |49 in a clockwise direction, as viewed in Figure 1, the outer sleeve of the servo-valve will be rotated and due to the action of the cam, it will be shifted to the right, as viewed InFigure 8, whereby port 9| will become connected to port |40 through the annular groove |44 in the inner sleeve. Thus uid pressure from pump |21 ilowing through channels |29, |30, and |39 to port |40, will be connected through line 90 to cylinder 89 causing movement of piston 81. It will be apparent that if no other change is made in the servo-valve, that this movement will continue uncontrolled by the servo-valve, and that is what happens for a predetermined length of movement, because the feed back connection is discontinuous, and does not become effective until after the wheel slide has moved a predetermined distance to bring the grinding Wheel close to the work.

The feed back mechanism is in the form of a linkage comprising a iirst lever |54 which is pivotally connected at |55 to the end of plunger |09. The lever |54 is integral with lever |56 and connected by a link |51 to a lever |58 which is pivotally mounted at |59 in such a position that the free end of lever |58 is in alignment with an operating plunger |60 movable with the screw |5. When the wheel slide is in its retracted position, the end of plunger |60 is out of contact with the lever |58 thus forming a discontinuous connection between the moving slide and the plunger 09. The lever 58 is urged in a clockwise direction by the spring ||0, but its movement is limited by the shoulder ||2 onthe plunger abutting the shoulder ||1 of the housing 5.

After the grinding wheel has been brought into close proximity to the work at a rapid rate due to the uncontrolled ilow to the cylinder 89, it is desirable that the remaining movement of thewheel slide be effected under control of a monitor or governor so that the rate can be positively held to a predetermined amount. The feeding rate of the servo-valve is effected by a hydraulic motor which must be started when the feed back connection is established, and in order to keep the movement continuous, it is desirable that the motor be started before the inner sleeve of the servo-valve is shifted to close port 9|. Therefore, a lost motion connection is provided between the plunger |09 and the sleeve 01 which is equal to the distance between the shoulder 2 on the end of plunger |09 and the flange ||3 on the end of the inner sleeve |01 as more particularly shown in Figure 9. In other Words, when the lever |58 is rotated in a counterclockwise direction by the plunger |60 to cause movement of the plunger |09 to the right as viewed in Figure 9, the shoulder ||2 will move into engagement with the ilange H3, because the spring ||0 is weaker than the spring |08. This means that the plunger |09 will move toward the right relative to the sleeve |01.

The annular groove ||8 formed in the plunger 09 and which,` as previously stated, was in a position to connect port ||9 with the port |20, will now be positioned to connect port H9 with port |3|. The port |3|, being a pressure port, will thus connect the pump |21 to channel |2| whereby iluid pressure will enter chamber |23 of the automatic start and stop valve |24 and shift the plunger |26 into its left hand position in which it is shown in Figure 8.

The fluid in the chamber |6| at the other end of the valve will be returned to reservoir through channel |62, port |63 of reversing valve |31, groove |64 in the reversing valve plunger |65, and port |66 to the return line |22. A check valve |61 located in channel |62 will open to permit this escape of fluid while still maintaim ing the channel full of oil.

The start and stop valve |24 has a pair of motor ports |68 and |69Which were interconnected by the annular groove |10 in the start and stop valve plunger when the same was in its right hand position. The port |68 is connected by channel |1| to annular groove |12 of the manually operable start and stop valve |13, This annular groove is connected by channel |14 to port |15 of the hydraulic motor indicated generally by the reference numeral |16. The other port |69 is connected by channel |11 to annular groove |18 of the manual start and stop valve |13. This groove is connected by channel |19 to port of the hydraulic motor |16. The motor |16 power rotates the outer sleeve of the servo-valve and to this end the motor is provided with an elongated piston |8| on the upper side of which is formed rack teeth |82 which, as shown in Figure 6, intermesh with pinion |83 attached to the outer sleeve of the servo-valve. The other side of the plunger is provided with a second set of rack teeth |84 which intermesh with a pinion |85 integral with the shaft |86. The pinion |85 intermeshes with rack teeth |81 formed on the periphery of a pilot valve actuating sleeve |88. i

The shaft |86 has a second pinion |89 which intermeshes with rack teeth |90 formed on the periphery of a rapid traverse control valve plunger |9|, It should now be evident that when the piston of the hydraulic motor is reciprocatcd,

that it will effect rotation of the outer sleeve of the servo-valve, and thereby through the cam cause axial movement thereof; and also that it will cause simultaneous reciprocation of the pilot valve sleeve |88 and the rapid traverse control valve plunger |9|.

Fluid pressure is supplied to the servo motor |16 from pump |21 through channel |32, and port |36 of the reversing valve which is interconnected by annular groove |92 in the reversing valve plunger |65 to port |93, and channel |90. This channel is connected through two different paths to port |95 of the start and stop valve. Thesel paths are connected in parallel, one path leading through the rapid traverse control valve whereby the fluid ilows unthrottled to the hydraulic motor, and the other through a rate control valve which the ilow to yield various rates of movement of the servo-valve. To this end the channel |94 has a rst branch |96 leading to port |91 of the hydraulic motor |16. This port is in constant communication with an elongated annular groove |98 formed in the periphery of a sleeve |99 carried by the piston |8|. This groove is also in constant communication with a port 200 which is connected by channel 20| to port 202 of the rapid traverse control valve indicated generally by the reference numeral 209.

This valve has a second port 204 which is normally interconnected with port 202 through an annular groove 205 formed in plunger 206. This plunger is held in the position shown by a springr 201, interposed between the end of the plunger and the end of 4the valve casing. The spring holds the plunger against the head 208 of a rod 209 which passes centrally through the plunger and is threaded in the end of the valve housing.

is adjustable to variably throttle f |01 a sufficient distance to From port 204 the fluid continues through a channel 2|0 to port 2|| of the hydraulic motor, and this port is continuously connected through anannular groove 2|2 formed in the sleeve |99 to port 2|9. This port is connected by channel 2|4 to port, |95 of the start and stop valve |24.

The channel |94 has a second branch 2 I 5 which terminates in ports 2|9 and 2|1 of the rate control valve indicated generally by the reference numeral 2I8. This valve has a plunger 2|9 on which is formed a tapered spool 220 movable relative to the port 2|9 for variably throttling the flow through that port. The tapered spool terminates in an annular groove 22| which is in continuous communication with port 222 which leads to channel 2|4 and thereby to port |95 of the start and stop valve. Since the path through the rate control valve offers a higher resistance to flow, than the path through the rapid traverse control valve, it will be apparent that when the port |99 is first connected to port |99 that the fluid will flow through the path of least resistance and therefore through the connection established by the rapid traverse control valve.

summarizing the operation of the mechanism as described so far, the manual control lever |49 located on the front 'if the machine is manually moved a limited amount whereby the outer sleeve o f the servo-valve is advanced relative to the inner sleeve a suiiicient amount to establish a fluid pressure connection to cylinder 89. Piston 81 moves at a comparatively fast rate to advance the grinding wheel to close proximity to the work, and then picks up the feed back mechanism. Through the kmeans of the feed back linkage, the plunger |09 in the servo-valve is moved to the right to take up the lost motion between it and the inner sleeve and against the compression of spring ||0, and in so doing, establishes a pressure connection which automatically shifts the start and stop valve into a position which connects pressure to the hydraulic motor |19. This causes movement of the hydraulic plunger which will now rotate the outer sleeve of the servo-valve in the same direction that the hand lever |49l` moved it and before the feed back has positively moved the inner sleeve close the port 9|.

From this point on the servo-valve will control the movement of the grinding wheel.

As the piston |8| advances, the uid in the low pressure end of the cylinder returns lto reservoir through port |15, channel |14, groove |12, channel |1|, port |99 of the automatic start and stop valve, annular groove |10 of plunger |29, port 229, channel 224, annular groove 225 in valve |19.

channel 229, port 221 of reversing valve |91, annular groove 228 in reversing valve plunger |99, and port 229 to the reservoir line |22.

As previously explained, the plunger |9| of the rapid traverse control valve 209 is being continuously moved by the piston |8| through the rack and gear connection, and the purpose of this valve is to permit an additional rapid traverse movement of the grinding wheel so that no time will be lost in bringing the wheel into contact with the work. This last additional rapid traverse movement is made variable as to length of stroke to compensate for variations in the amount of excess stock on the work. To this end the plunger 9| has an adjustable sto'p member 290 threaded into it so that by rotating the stop member, the amount that it projects beyond the plunger |9| may be varied.

This rotation may be effected from an external point through means of the renewing mechanism. The stop member 290 is provided with a splined extension 29| which passes bore of a worm gear 292 rotatably mounted in the end of the valve housing. Thisworm gear, as shown in Figure 6, intermeshes with a worm 299 secured to the end of a vertical shaft 294, which has a keyed connection with the h ub of a bevel gear 295. This gear intermeshes with a second bevel gear 299 secured to the end of shaft 291. 'Ihis shaft projects beyond the housing 298 and is provided with a threaded portion 299, and an operating knob 240. The portion 299 is threaded in a barrel 24|, and a skirt 242 depending from the knob 240 telescopes the barrel to provide micrometer adjustment. In other words, cooperating micrometrical graduations may be placed on the skirt and barrel to insure accurate setting of the stop member.

As the plunger |9| is advanced, the stop member will engage the end of plunger 209 and shift the same a sufficient distance to disconnect ports 204 and 202 whereby the motor supply fluid will now have to pass through the feed rate control valve 2|8.

The feed rate control valve may be adjusted by a mechanism, such as that shown in Figure '1, for varying the rate of movement of piston |8|. This mechanism comprises a. bell crank 249 which interconnects the plunger 2|9 to an adjustable plunger 244. Plunger 244 is keyed in a sleeve 245 which is rotated by the manually operable disc 249 having a depending shaft 241 splined in the end of the sleeve. The sleeve carries a roller 248 which is movable in a cam slot 249 formed in a depending skirt 250. The cam slot is so arranged that upon rotation, the sleeve 245 will be moved axially thereby effecting rotation of the bell crank 249 and axial movement of plunger 2|9 which is normally urged in one direction by a spring 25|.

The piston |8| will now move at a slower rate dependent upon the setting of the feed rate control valve, and the rate of axial movement of the servo-valve will then depend upon the rate of movement of the piston |8| and the helix angle of the cam groove |04. This movement will continue until the reversing valve is tripped, and the positive stop engaged.

The shifting of the reversing valve is controlled by the pilot valve |95 and this valveA has a plunger 252 which has a lost motion connection with the operating sleeve |88 comprising a slot 259 formed in the plunger and a pin 254 carried by the sleeve.

through a splined It will be noted from Figure 6 that the sleeve |88 will travel in a. direction opposite to that in which the piston |8| moves due to theplnion connection between them. Therefore, the sleeve |88 will be moving downward toward the bottom of the sheet pin 254 picks up start to as viewed in Figure 8 until the |22 and admit fluid pressure to channel 299 and port 292 of the reversing valve. Since this port is closed at this time, the fluid Ipressure will be forced through channel 294, past check valve 295,

and through the tarry control valve 266 to c-hannel 261 which terminates in port 268 located in the extreme end of the reversing valve. 'I'he tarry valve has a plunger 269 which is similar in construction to the feed rate control valve, and adjustable by similar means, whereby the rate of flow of fluid to the reversing valve may be varied to provide a certain time delay whereby the grinding wheel may spark out before returning.

After sufllcient pressure has built up in channel 261, the reversing valve plunger |65 will be fired to its other extreme position whereby groove 228 will interconnect the pressure port |36 to port 221; and the annular groove |64 will interconnect port |63 with port 21|. The port 21| being connected at this time through channel 212 to port 258 of the pilot valve, which in turn is now connected to the reservoir line |22, it will be apparent that the line |62 is now a reservoir line. The shifting of the pilot valve plunger also resulted in the annular groove |92 interconnecting port |93 to reservoir port 213. Since the port 221 is now underpressure, fluid will flow through line 226 to port |15of the hydraulic motor |16, and the fluid in the other end of the motor will return to reservoir through port |80, channel |19 and the two start and stop control valves to channel 2 I4. This channel leads through the hydraulic motor to port 204 of the rapid traverse control valve, but since this port is closed, the fluid will be forced to go through the port 222 of the feed rate control valve and open check valve 214 mounted in the interior of the piston 2|9. The fluid will then continue through port 2| 1, channel 2|5 to port |93 of the reversing valve which at this time is connected to the reservoir port 213.

. The piston 8| will return at a. faster rate due to the fact that the fluid is being bypassed through the feed rate control valve whereby less resistance is set up to the return of fluid to reservoir. The piston |8| will, through the mechanical connections, advance the outer sleeve of the servo-valve in a return direction until the motor port 9| is connected to the exhaust port |43 whereby the pressure in cylinder, 95 will cause return movement of the wheel slide. The piston |8| will continue to move withdrawing the stop 230 in the rapid traverse control valve, whereby the ports 204 and 202 will become interconnected again but the check valve 215 in the channel 20| will prevent ow through this part of the system. Eventually the inner sleeve |01 of the servo-valve will engage the shoulder ||4 of the housing thereby f preventing further movement thereof, whereby a further movement of piston |8| will open port 9| a little more permitting a more rapid movement of the Wheel slide. When this has been accomplished, the piston |8| will have reached the end of its stroke whereby the slide will return at a rapid rate, and the feed back plunger |09 will move relative to the inner sleeve and close port |38, and eventually interconnect port |20 with port ||9 whereby the chamber |23 of the automatic start and stop valve |24 will be connected -to reservoir.

When the pistony 8| reaches the end of its stroke,l it will have moved the pilot valve a suincient distance to cause automatic firing thereof and thereby interconnected pressure port |33 to port 258 whereby the fluid will flow to port 21| of the reversing valve. With the reversing valve plunger at the lower end of its stroke, the port 21| is connected to port |63 as well as to the end of the valve housing. The port |63 leads through channel |62 and check valve 216 to the left hand `end of the start and allegare stop valve |241 whereby the fluid pressure will act in chamber |6| to shift the plunger |26 to the right thereby interconnecting motor ports 168 and |69. This will occur before the plunger |65 moves upward, due to the fact that the resistance to shift the plunger 26 is less than that to move the plunger |66, because the fluid escaping through port 268 in the other end of the plunger must pass through channel 261 and check valve 211. The fluid continues to reservoir through port 256 of the pilot valve, annular groove 255 and port 218. By setting the check valve 211 to a higher resistance than the check valve 216, the valve plunger |26 will be shifted, before the reversing valve plunger is shifted, thereby interconnecting both ends of the motor |16 before pressure is admitted to start the next movement. This leaves the parts in a starting position with the motor port 9| of the servo-valve connected to the reservoir port |42 whereby the wheel slide will continue its return movement until the piston 81 contacts the end of the cylinder 89.

Since the piston |8| completed its entire return stroke under power, the lever |49 will be returned to its extreme starting position, and since the ends of the motor are interconnected, it is possible for the lever to be manually advanced a predetermined distance thereby advancing the piston |8|, without undue resistance.

Provision has been made whereby the headstock motor 219, shown in Figure l, may be automatically started when the automatic start and stop valve plunger |26 is power shifted into the position shown in Figure 8. There is a limit switch 280 which has an operating plunger 28| carrying a roller 282. The roller rides on the periphery of a cam member 283 which is supported on a shaft 284. The cam member has gear teeth 285 cut in its periphery and intermeshing with rack teeth 286 formed on a plunger 281. The plunger is slidably mounted in cylinder 288 the opposite ends of which are connected by channels 289 and 290 to a selector valve 29|. It will be obvious that when pressure is admitted to one end of the cylinder and the other end is connected to exhaust, that the cam member will be rotated in one direction or the other to either start or stop the electric motor.

The selector Valve 29| has a plunger 292 which is operatively connected by a bell crank 293 to an operating rod 296i. This rod is adapted to be reciprocated by the same `means as that shown in Figure 7 for adjusting the valve plunger 2|9. The plunger 292 has two positions, the one in which it is shown in Figure 8 serves to interconnect channel 290`to the channel 2943 which terminates in port 295 of the start and stop valve, and also to interconnect channel 289 with channel 296 which terminates in port 291 of the start and stop valve. Thus, when the plunger |26 of the start and stop valve is power shifted to the left, the pressure port |61 will be connected to channel 296 thereby shifting the plunger 281 to the right rotating the cam 289 in the position to close the electric limit switch. The other end will be connected to reservoir through interconnected channels 296, 296 and interconnected ports 295 and 298 of valve |243 to line |22.

When the machine is stopped and the plunger |26 is shifted to the right, pressure port |9| will be connected to channel 299 and port 291 will be connected to exhaust port 299, whereby the plunger 281 will be shifted to the left thereby opening the limit switch.

' ing wheel support,

- to the movable support, a

When the machine is being hand controlled as by the control lever 33 shown in Figures 1 and 5, the automatic start and stop valve plunger |26 will, of course. not be shifted, and therefore means have been provided whereby the headstock motor may b e started and stopped in spite of the position of plunger |26. This is accomplished by throwing the selector valve plunger 292 to the right soas to disconnect channels 290 and 289 from channels 294' and 296 respectively, and interconnecting them with channels 300 and 30|. These two are connected to a manually controlled start and stop valve indicated generally by the reference numeral 302 which has a pressure port 303 and an exhaust port 304. When the operating lever 305 for this valve is in the position shown, it will be apparent that the pressure port 303', which is supplied by the pump 1|, is connected through channel 300 and 290 to the right hand end of cylinder 208 which will cause rotation of the cam 283 into a position to stop the headstock motor. When the lever 305 is thrown to the left, the port 303 will be connected to channel 30| which will cause shifting of the plunger 291'to the right and thereby cause actuation of the headstock. Thus means controlling operation of the headstock motor when the machine is under manual control.

There has thus been provided an improved automatic control mechanism for determining a relative movement between a grinding wheel and a work support which will yield different methods of control, and which, when under automatic control, will produce a highly erllcient cycle of operation and thereby make it possible to grind nished work pieces in al minimum amount of time.

I claim:

l. In a grinding machine having a bed, a grindand a work support, the combination of means for effecting relative movement between said supports including a screw and nut, one of which is attached to the bed and the other first power operable member for effecting bodily movement of said screw and nutin one direction, a second power operable member for effecting power movement of the screw and nut in a second direction, means to selectively cause actuation of either of said members, a manually operable means and a power operable means for effecting relative rotation between the screw and nut, and means to selectively connect eithe of said last named means to effect said relative rotation during power movement of said support by either of said first two named members.

2. In a grinding machine having relatively movable work and grinding wheel supports, the combination of means for effecting relative movement between the' supports including a rotatable member, motion transmitting means coupling saidmember for effecting said movement, means for rotating said member including a power operable device, a clutch for connecting said device tol said member, a rack shifting said clutch, a manually operable control lever for rotating said segment, and means operable by said lever after rotation of said segment for causing actuation of said device.

3. In a grinding machine having relatively movable work and grinding wheel supports, the combination of means for effecting relative movement between said supports including relatively movable threaded parts, a shaft operatively conchannels, as shown in Figure 5,

have been provided for and gear segment for nected for effecting relative movement between .said parts, a fluid operable device, a shiftable clutch for connecting said device to said shaft, a shifter having resilient connections with said clutch, a rotatable cam for actuating said shifter, a control valve including a rotatable sleeve and an axially movable plunger, motion transmitting means connecting said sleeve to said cam, and a control Iever movable in one plane for rotating said sleeve to effect clutch engagement and in a.4

second plane for moving said plunger to cause power actuation of said device.

4. In a grinding machine having relatively movable work and grinding wheel supports, the combination of means for effecting relative movement between threaded members, one of the movable support, a drive relative movement between said threaded members, a uid operable motor, a clutch for con-- necting said motor to said shaft, a control valve including a rotatable sleeve and an axially movable plunger,

which is attached to said supports including cooperating shaft for effecting mechanical means connecting said sleeve i'or eifecting engagement-of said clutch A upon rotation of the sleeve, a source of iiuid pressure connectible by axial movement of said plunger to said motor, and a common control lever for selectively actuating said sleeve and plunger.

5. In a grinding machine having a work support and a grinding wheel support, the combination of means for eiecting relative movement between the supports including a drive shaft, a fluid operable motor, a shiftable clutch for connecting said motor to said shaft, a motor control valve including a rotatable sleeve and an axially movable plunger, a bayonet joint betweensaid sleeve and plunger whereby said sleeve must be given a predetermined rotation before said plunger can be moved, a source of pressure, detent means for holding said plunger in a motor stop position, resiliently operable means for rotatably urging said sleeve intolocking engagement with said plunger, clutch shifting means operatively connected to said sleeve, a control lever operablef in a first plane for rotating said sleeve to cause engagement of the clutch and unlocking of said plunger, and in a second plane for moving said plunger to cause selective engagement of said fluid pressure for opposite actuation motor; and resiliently operable means acting on said first detent for centralizing said plunger upon release ofthe lever whereby said first named resiliently operablemeans will return said sleeve to effect disengagement of said clutch and locking of 'said plunger.

6. In a grinding machine having a worlr'v support and a grinding wheel support, the combination of means for effecting relative movement ber/tween the supports including relatively rotatable threaded members, one of which is attached to the moving support, a piston operatively connected to said xed member for causing bodily movement thereof in one direction, a second fluid operable piston operatively connected for causing bodily movement of said movable member in 'a second direction, a third fluid operable member for eifectlng relative rotation -between said threaded members to cause actuation of said movable member'in either one of two directions,

a first control for said first two named pistons,

of said l and a second control for causingactuation of y Ysaid last named fluid operable member at will during actuation ornonactuation of either of said pistons.

7. In a grinding machine having a work support and a grinding wheel support, the combination of means for effecting relative movement between the supports including a fiuid operable piston, a source of fluid pressure, a servo control Valve having relatively movable parts, means to shift one of said valve parts to connect uid pressure to said piston, a feed back connection to said second valve part, and means carried by the movable slide to pick up and move said feed back connection after a predetermined movement of said piston whereby said slide can be moved at a fast rate uncontrolled by said servo valve, and at a subsequent slower rate under control of said servo valve.

8. In a grinding machine having a work table and a grinding wheel support, the combination of means for moving one of said parts toward the other including a fluid operable piston, a source of pressure, a servo valve comprising relatively movable parts, manually operable means for advancing one of said parts relative to the other to connect said source of pressure to said piston,

' a motor operatively connected for power advanci valve, power operable ing said first named part, a feed back connection to said second named part, and means engageable by said slide after a predetermined advancing movement thereof to cause actuation of said feed back, and means operable by said feed back for causing actuation of said motor.

9. In a machine tool having a work support and a tool support, the combination of means for effecting relative movement between said supports including a fluid operable piston, a source of fluid pressure, a servo valve, a first means for positioning said servo valve to connect said fluid pressure to said piston, a feed back connection having a lost motion connection with the servo means for actuating said servo valve, and means operable by the feed back to start said power operable means during take up of said lost motion.

10. In a machine tool having a work support and a tool support, the combination of means for effecting relative movement between the supports including a fluid operable piston, a servo control valve for connecting a source of fluid pressure to said piston, a discontinuous feed back connection from the moved part to said servo valve, a manually operable control lever movable in one plane for causing manual actuation of said servo valve whereby said piston Will move at a constant rate for a predetermined distance without actuating anism, power operable means for actuating said servo valve, means'operable upon actuation of Said feed back mechanism by said piston to start said power operable means, and means connected for actuation by said lever in a second plane to stop said power operable means at will.

11. In a machine tool having a work support and a tool support, the combination of means for effecting relative movement between the supports including a servo motor control mechanism, manually operable means for initiating actuation of said servo motor mechanism, a power operable motor for continuing said actuation, an automatic start and stop valve for said motor, means operable by the feed back mechanism for shifting said valve to a running position, and manually operable means for bypassing said valve to stop said motor at will.

12. In a grinding machine having a bed, a. work support and a grinding wheel support mounted on said bed, the combination of means for effecting relative movement between said said feed back mech-- supports including a relatively movable screw and nut, one of which is attached to the bed and the other to said support, a manually operable `member for effecting relative movement between the screw and nut, a power operable member for effecting relative movement between the screw and nut whereby operation of either of said members will cause relative movement between the grinding wheel support and the work support, and additional means for effecting relative movement between said supports including a pair of piston and cylinder motors, and means to differentiate the pressures therein.

13. 'In a grinding machine having a bed, a work support and a tool support mounted on said bed, the combination of means for effecting relative movement between said supports including a relatively rotatable screw and nut, an actuator for effecting said relative rotation, a manually operable member and a power operable member selectively connectible to said actuator for causing movement between saidsupports, a first piston and cylinder for moving the tool support in one direction, a second piston and cylinder for moving the tool support in an opposite direction, means to maintain hydraulic pressure in one of said cylinders, means to differentiate the hydraulic pressure in the second cylinder with respect to the first to effect bodily movement of the screw and nut and thereby the connected tool support in either direction, and means to render any of said control means effective at will to cause relative movement between said supports.

14. In a grinding machine having a bed, a work support and a grinding wheel support, the combination of means for effecting a feeding movement of the grinding wheel support toward and from the work support including a relatively rotatable screw and nut, one of which is carried by the movable support, and the other attached to the bed, a shaft operatively connected for effecting relative rotation between the screw and nut, a manually operable member, a fluid operable motor, a clutch member oppositely shiftable for selectively connecting said member or said motor for rotation of said shaft, a control lever movable in one plane for shifting said clutch, a control valve for said motor having a source of pressure connected thereto, and means connecting said control valve to the lever when the same is moved in a direction at right angles to the first-named plane.

15. In a grinding machine having a bed, a work support and a grinding wheel support, the combination of means for effecting a feeding movement of the grinding wheel support toward and from the work support including a relatively rotatable screw and nut, one of which is carried by the movable support, and other attached to the bed, a shaft operatively connected for effecting relative rotation between the screw and nut, a manually operable member, a fuid operable motor, a clutch member oppositely shiftable for selectively connecting said member or said motor for rotation of said shaft, a control lever movable in one plane for shifting said clutch, a Control valve for said motor having a source of pressure connected thereto, means connecting said control valve to the lever when the same is moved in a direction at right angles to the i'lrstnamed plane, and automatically operable means effective when the lever is released to automatically return the same in both planes to a starting position.

16. In a grinding machine having a work supthird member in said valve, means voperable by the support after a predetermined movement thereof to shift said third member and efiect,.

first, a connection of uid pressure to said uid operable motor, and second, a shifting of the other valve part to cause follow-up of the movement of the iirst valve part.

CHARLES 

